Density control printer

ABSTRACT

A density control identification printer is disclosed which includes an enclosed film printing chamber and an energy storing and releasing system such as an electrically actuated condensor or capacitor for providing a source of controlled illumination. The top surface of the printing chamber is equipped with a translucent window of which one section thereof is adapted with a density-graded mask. The remaining portion of the window is sized and adapted to receive a notched printed information card. An unexposed portion of X-ray film is placed over the mask and information card and covered by a tight fitting lid. A switch is automatically actuated and a controlled amount of light is released whereby an image of the mask is transferred to the film. Concomitantly therewith, an image of the information printed on the information card is transferred to the film for identification use.

D United States Patent r1 1 r111 3,864,038

Palazzolo Feb. 4, 1975 DENSITY CONTROL PRINTER I [76] Inventor: James C. Palazzolo, 902 N. Main, [57] ABSTRACT Farmington, Utah 84025 A density control identification printer is disclosed which includes an enclosed film printing chamber and [22] Flled Sept 1973 an energy storing and releasing system such as an elec- [21] Appl. N0.: 398,442 trically actuated condensor or capacitor for providing a source of controlled illumination. The top surface of the printing chamber is equipped with a translucent window of which one Section thereof is adapted with a k 5 355/114 density-graded mask. The remaining portion of the 0 c window is sized and adapted to receive a notched printed information card. An unexposed portion of [56] References cued X-ray film is placed over the mask and information UNTED STATES PATENTS card and covered by a tight fitting lid. A switch is au- 1,261,177 4/1918 Strong 355/114 tomatically actuated and a controlled amount of light 1,832,294 Gent A is released whereby an image of the mask is transferred to the film. Concomitantly therewith, an image yman Primary Examiner-John M. Horan Attorney, Agent, or Firm-Trask & Britt of the information printed'on the information card is transferred to the film for identification use.

4 Claims, 5 Drawing Figures P/ TENTED B 7 26a 26b 26c 2 6: 26a

FIG. 2

FIG.3

, DENSITY CONTROL PRINTER BACKGROUND OF THE INVENTION 1. Field of the Invention This invention in directed to a means for transferring information on film and particularly to a method and apparatus for providing X-ray film with a densitygraded test strip for distinguishing between proper and improper film exposure times and/or film processing.

2. State of the Art When diagnostic radiology first came into use, the X-ray technician, who exposed the film, would normally also develop it. Under these conditions, the taking of the X-ray and its development permitted a certain degree of latitude as an experienced technician could always compensate for over or under exposure by shortening or prolonging development time. With this technique, errors in exposure time could be corrected and an acceptable X-ray image obtained. However, as the volume of work increased, the X-ray technician had little time for development thus'necessitating that another group of technicians became responsible for the films processing. With the advent of automatic film processing, variations in development time could no longer be relied on as a means for obtaining acceptable film images. It also became evident that if the developed film was either too dark. or too light or if the contrast was not acceptable, it was difficult to accurately determine whether the error was due to a film overor under-exposure or whether it was due to improper film processing. In many instances, a substantial number of X-rays had already been taken before the error was detected. When this occurred a second series of X-rays was required which not only increased X-ray costs but also caused serious inconveniences to patients who had to be removed from their beds and returned to the X-ray room for further film taking.

To overcome the above problems, a service was instituted whereby a pre-exposed film strip was sent to film users who were asked to develop the strip and record specific processing information. The film strip was then returned to the servicing company for densitometric analysis. This service was soon discontinued when it was found that a control strip with an aged latent image is less sensitive to variations in film processing than are radiographs or control strips processed immediately after exposure.

OBJECTS OF THE INVENTION It is, therefore, a primary objectof this invention to provide a simple and inexpensive means for detecting variations in film exposure and/or processing immediately after exposure. Another object is to provide an apparatus for marking film with a test strip capable of distinguishing between improper film processing and incorrect exposure times. Still another object is to provide a printing apparatus and method for simultaneously transferring identifying information and a den-' sity-graded test strip to the X-ray film. Another object is to provide a means for continuously monitoring film exposure and/or film processing. 1 I

SUMMARY OF THE INVENTION The above objects are attained by the density control identification printer of this invention which includes a film printing chamber having enclosed therein an illuminatingsource and an energy storing and releasing means. The top surface of the printing chamber is provided with a translucent window wherein one section thereof is adapted with a density-graded mask. The other section is sized for receiving a notched printed information card. A section of unexposed film- (normally upper left hand corner of film) is placed over'the window containing the mask and information card and covered by a tight fitting lid. Upon actuation of a switch, a controlled, predetermined amount of luminescence is released, transferring the mask and the printed information on to the film. If the'film is properly developed, the transferred mask will compare favorably, both in density and contrast, with a preselected standard. This indicates that if the X-ray image is either too light or too dark, it was probably due to incorrect exposure time and not due to improper film.

processing. Conversely, if the mask does not corre-,

- spond to the standard, the technician is alerted and the film processing procedures and/or the chemicals used in developing the film are immediately checked.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a three dimensional view of the printer of this invention.

FIG. 2 is an electrical diagram depicting the source of the printers light energy source.

FIG. 3 is an enlarged top elevation of the masked window section of the printer shown in FIG. 1.

FIG. 4 is a top view of a notched identification card.

FIG. 5 is a top view of a standard X-ray film having identifying information and a density strip recorded thereon.

DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in the accompanying drawings, and particularly FIG. 1, the printer of this invention includes an enclosed printing chamber 10 having an illuminating source 12 (FIG. 2) actuated by a switch 14. A translucent window 18 is provided in the top. wall of the chamber 10 wherein the window is characterized by having a density-graded mask 26 affixed to or etched on the windows upper section 20. The lower section. of the window 22 is reserved to receive an identification card- 24. Data from the identification card 24v (FIG. 4) is transferred to the film by placement of the film over window section 22 and actuating a light source. As indicated above, the windows upper section 20 is adapted to receive a translucent density-graded film mat strip 26 affixed thereto (FIG. 3). In lieu of the mat strip, the window section 20 maybe etched or painted to provide a film image equivalent to that obtained from a film mat strip. The mat .strip is divided into a plurality of sections, 26a through 26c inclusive, each section being a different and contrasting shade or tone of film density. For purposes of the disclosure and claims of this invention, density is defined as the logarithm of the ratio of the light incident on the film to the light transmitted by the film; that is, the logarithm of the reciprocal of transmittance D= Log wherein D is the density and Tis the transmittance. Contrast is defined as density difference.

As shown in FIG. 3, sectionf26b is s iibstantially opaque while section 262 is relatively clear. The intermediate sections 26b, 26c and 26d are density-graded to contrast between the clear and opaque end sections. When the mat strip is transferred to the film via the printing. box, the resulting strip represents a scale which, when compared to a standard (by visual inspection or by use of a densitometer), advises the technician as to whether the exposure and/or developing procedures of the film were proper. If the test strip does not compare favorably with the standard, the technician is alerted as to possible inconsistencies in the developing procedures. For example, the chemicals, temperatures and developing times would be immediately checked by the technician to determine the cause for the unfavorable comparison. With this system a continuous control is maintained on the developing process with an immediate determination as to whether an improper image was due to faulty developing and/or to improper X-raying techniques.

A lid 28 is mounted along one side of the printing box 10 by meansof a spring loaded hinge 29. The bottom surface of the lid is layered with a soft black velvet 30 or other light-leak inhibiting materials such as foam rubber for containing the light within the printing box and preventing light from the outside to fog or otherwise adversely effect'the unexposed film. Along one of the sides of the printing chamber 10, an exposureindicating window 32 is mounted for indicating to the technician, by visual observation, when the illuminating source has been actuated. A volt meter 34 is carried on the top wall of the printing chamber 10 for continuously reporting the line voltage'of the illuminating circuit. The voltage may be varied through a knob 36 operatively connected to a voltage regulator 41. Avariable resistor 38 is also provided for finer adjustments. By varying the resistance on the voltage regulator and variable resistor, a constant and steady line voltage may be maintained. This insures that a constant amount of light energy is released during each printing. If desired, a more sophisticated system may be' incorporated to automatically monitorand control the line voltage.

As shown in FIG. 2 the electrical circuit of the energy storage and releasing means comprises a power source 40, normally 1 10 volts, a voltage regulator 41, a switch 14 electrically connected to a variable resistor 38 and a capacitor 42. A light source 44, which ispreferably a strobe light, is series-connected such that upon actuation of the switch (as by closing the lid of the printing chamber), the capacitor will discharge a constant, reproducible voltage pulse for actuating the light source. A capacitor or its equivalent, i.e., a device which has the ability to accumulate energy at a slow rate and then suddenly discharge the stored energy, is a vital element in this electrical circuit. A variable resistance means is also critical since the intensity and duration of the flash is a function of voltage and time. The resistance, therefore, must be capable of being varied in order to match the capacitance and thereby provide a constant light intensity. 7

Although a strobe light is described as the preferred illuminating source, other types of electronic flashes may be used. For example, a Xenon flash lamp may also be used. With this type of lamp, the xenon contained within a glass tube is ionized by a voltage pulse discharged from a capacitor.

In FIG. 4 an identification card 24 is depicted wherein the top portion is adaptedwith a notch 54 or indentation for receiving and framing the film density strip 26 shown in FIG. 3. The patients name and other vital information is recorded on the cardsface'for transference to the film. Generally, the identification card is of such thickness that the light will .pass therethrough transferring the typedoriprinted information directly to the film.

In FIG. 5, a typical X-ray film 56 is shown wherein 5 the upper left-hand corner portion 58 thereof contains the information transferred from the identification card of HO. 4 and the film density strip depicted in F IG. 3.

In operation, the technician places the patients information card 24 in the window 18 of the printer 10. The film is removed from a cassette and, with the aid of a safety light, the unexposed portion of the film (a portion protected by a lead strip) is pla'cedover the transluscent matstrip 26 and the information card 24. The lid 28 is then closed holding the film firmly in position. As the lid is closed, the switch 14 is actuated releasing a constant and predetermined amount of light transferring the information from the mat strip 26 and information card 24' to the film. The film is then removed and developed in normal fashion. Periodically the technician should check the volt meter to determine if the line voltage has varied from the desired value. if it-has, the knob36 is rotated adjusting the voltage regulator 41. Since an exact and predetermined amount of light is released each time-the switch is actistrip. If a variation in density or contrast is detected in the strip, the development time and chemical strength should be immediately checked. lf the strip compares favorably to the standard, and if the image on the X-ray film is still too light or too dark, the X-ray technician should be advised so that corrective actions may be .taken.

While the invention has been described with reference to specific embodiments, it should be understood that certain changes may be made by one skilled in the art and would not thereby depart from-the spirit and scope of this invention which is limited only by the claims appended hereto.

l claim:

1. A density control and identification printer for transferring adensity control strip andidentifying information to an unexposed portion of exposed X-ray film comprising:

means contained within said chamber for transmitting a constant and reproducible amount of light energy, a translucent window positioned in the top wall of contains a gradedfilm density strip and the remaining segment of said window provides space to receive an identification card containing identifying information, said film density strip being characterized by a series of graded densities which, when transferred to said X-ray film, will provide information as to whether said X-ray film has been properly processed and/or whether the X-ray film was properly exposed.

2. The printer of claim 1, wherein the energy storing and releasing means includes a capacitor electrically connected to an illuminating means.

3. The printer of claim 2, wherein means is a flash lamp.

4. A density control and identification printer for transferring a density control strip and identifying information to an unexposed portion of exposed X-ray film comprising:

vated, the test strip should be identical to the standard a printing chamber and energy storing and releasing said chamber wherein one section of said window the illuminating 6 information, said film density strip being characterized by a series of graded densities which, when transferred to said X-ray film, will provide information as to whether said X-ray film has been properly processed and/or whether the X-ray film was properly exposed.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,864,038 Dated February 4, 1975 Inventods) James C Palazzolo It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Col. 2, Line 61, change "D Log f t0"D Log Signed and Scaled this second Day of March 1976 [SEAL] Attest:

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner ofParenrs and Trademarks UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,864,038 Dated February 4, 1975 lnventor(s) James C. Palazzolo It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Col. 2, Line 61, change "D Log to--D Log i Signed and Scaled this second Day Of March 1976 [SEAL] Attest:

RUTH C. MASON C. MARSHALL DANN Arresting Office Commissioner oflatenls and Trademarks 

1. A density control and identification printer for transferring a density control strip and identifying information to an unexposed portion of exposed X-ray film comprising: a printing chamber and energy storing and releasing means contained within said chamber for transmitting a constant and reproducible amount of light energy, a translucent window positioned in the top wall of said chamber wherein one section of said window contains a graded film density strip and the remaining segment of said window provides space to receive an identification card containing identifying information, said film density strip being characterized by a series of graded densities which, when transferred to said Xray film, will provide information as to whether said X-ray film has been properly processed and/or whether the X-ray film was properly exposed.
 2. The printer of claim 1, wherein the energy storing and releasing means includes a capacitor electrically connected to an illuminating means.
 3. The printer of claim 2, wherein the illuminating means is a flash lamp.
 4. A density control and identification printer for transferring a density control strip and identifying information to an unexposed portion of exposed X-ray film comprising: a printing chamber and an illuminating source contained within said chamber for transmitting a desired amount of light energy, a translucent window positioned in the top wall of said chamber wherein one section of said window contains a graded film density strip and the remaining segment of said window provides space to receive an identification card containing identifying information, said film density strip being characterized by a series of graded densities which, when transferred to said X-ray film, will provide information as to whether said X-ray film has been properly processed and/or whether the X-ray film was properly exposed. 